let-else: add tests for moved expressions, copy out of non-copy

This commit is contained in:
Cormac Relf 2021-10-13 18:34:29 +11:00
parent 34a98192d5
commit 61bcd8d307
2 changed files with 62 additions and 0 deletions

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// run-pass
//
// This is derived from a change to compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs, in
// preparation for adopting let-else within the compiler (thanks @est31):
//
// ```
// - let place = if let mir::VarDebugInfoContents::Place(p) = var.value { p } else { continue };
// + let mir::VarDebugInfoContents::Place(place) = var.value else { continue };
// ```
//
// The move was due to mir::Place being Copy, but mir::VarDebugInfoContents not being Copy.
#![feature(let_else)]
#[derive(Copy, Clone)]
struct Copyable;
enum NonCopy {
Thing(Copyable),
#[allow(unused)]
Other,
}
struct Wrapper {
field: NonCopy,
}
fn let_else() {
let vec = vec![Wrapper { field: NonCopy::Thing(Copyable) }];
for item in &vec {
let NonCopy::Thing(_copyable) = item.field else { continue };
}
}
fn if_let() {
let vec = vec![Wrapper { field: NonCopy::Thing(Copyable) }];
for item in &vec {
let _copyable = if let NonCopy::Thing(copyable) = item.field { copyable } else { continue };
}
}
fn main() {
let_else();
if_let();
}

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// run-pass
// issue #89688
#![feature(let_else)]
fn example_let_else(value: Option<String>) {
let Some(inner) = value else {
println!("other: {:?}", value); // OK
return;
};
println!("inner: {}", inner);
}
fn main() {
example_let_else(Some("foo".into()));
example_let_else(None);
}